Answer

There have been 18 occasions so far in 2014/15 when planned overnight maintenance activity has extended into the start of passenger services.

I am glad to say that between 2010/11 and 2013/14 (the last full year of figures) the number of such occasions fell by 23 per cent.

As a proportion of all delays to customers these occasions account for around a tenth of one percent (0.11 per cent).

A number of measures are in place to reduce the occurrence of engineering overruns, including:

New technology which measures the condition of track and rail to predict degradation of assets. This enables defects to be removed in a planned manner without impacting on the railway.

Increased investment in rail grinding/milling across the network to prevent more serious defects developing.

Smarter stock control to ensure sufficient tools and parts are available to cover breakage and malfunction.

Thorough pre-work staff briefings to confirm plans for the night, with checks throughout the night to ensure that work is running to time.

Further reductions are expected as a result of an additional £10 million per year investment in London Underground’s maintenance programme from 2015/16. This extra investment will be used specifically to improve the condition of rails, reducing the potential for defects requiring urgent attention that may result in engineering overruns.